Cardiac surgery is traditionally performed through a median sternotomy, providing optimal access to all cardiac structures and great vessels, but generating significant disfigurement and pain for the patient. The advent of robot-assisted minimally invasive surgery (MIS) holds great promise for improving the accuracy and dexterity of a surgeon while minimizing trauma to the patient. However, clinical success with robot-assisted cardiac MIS has been marginal; improved patlent outcomes and mitigated costs have not been proven. We hypothesize that this is due in large part to the lack of haptic feedback presented to the surgeon. Without the sense of touch naturally used in surgical tasks such as fine suture manipulation, surgeon performance is jeopardized. The general objective of the proposed research is to acquire and use haptic information during robot-assisted minimally invasive surgery, with a focus on manipulation of fine sutures. It is anticipated that this approach will offer two main benefits over current systems: (1) forces will be fed back to the user in real time, directly or through sensory substitution, improving task performance, and (2) haptic information will be used to create automatic virtual fixtures that assist the surgeon, e.g., by prevention of excessive applied suture forces and maintenance of constant retraction forces. The specific aims are: (1) to understand the sensing requirements for minimally invasive surgical tasks, (2) to test different modes of haptic feedback in robot-assisted minimally invasive surgical environment, (3) to create virtual fixtures that augment and improve the execution of surgical tasks, and (4) to apply feedback of haptic information during phantom experiments, creating a direct path to clinical applications. These specific aims contribute to a Iong-term research plan for using haptic information in robot-assisted minimally invasive surgery. The proposed work represents the development of operative technology that can provide significant improvements in patient outcomes, as well as Iay the groundwork necessary to address several other exciting research issues such as beating-heart (off-pump) procedures, procedure and tissue models, and virtual environments for training.